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App Dev Worksheet: Functions

App development lesson 20: Functions · Set 866 · 40 questions
TalentJR

Developer's tip (Write once, use often): function name(parameter) { …; return result; } — call it with name(value). Work out each call separately, then finish the line. Inside a function, if / return can give different results for different inputs.

NameDateTime takenScore ___ / 40
  1. 1.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(1) + points(5));
  2. 2.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 60;
    }
    show(fee(2) + fee(8));
  3. 3.🧰 What is a function? (a) a screen size (b) a type of phone (c) a named block of code (d) a list of colours
  4. 4.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(36));
  5. 5.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(0));
  6. 6.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Zoya"));     (a) Hello, Zoya! (b) Zoya (c) Hello, name! (d) greet
  7. 7.🧰 Why write a function? (a) to hide errors (b) to make code longer (c) to reuse code (d) to slow the app
  8. 8.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(25, 5));
  9. 9.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(5));
  10. 10.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(3) + points(4));
  11. 11.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Zoya"));     (a) Well done, Zoya! (b) Well done, name! (c) greet (d) Zoya
  12. 12.🧰 What does this code show?
    function greet(name) {
      return "Hi, " + name + "!";
    }
    show(greet("Arjun"));     (a) Arjun (b) greet (c) Hi, name! (d) Hi, Arjun!
  13. 13.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 50;
    }
    show(fee(2) + fee(5));
  14. 14.🧰 What does return do in a function? (a) closes the screen (b) repeats the code (c) sends back a value (d) deletes the app
  15. 15.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 60;
    }
    show(fee(3) + fee(2));
  16. 16.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(22));
  17. 17.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 30;
    }
    show(fee(3) + fee(2));
  18. 18.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 40;
    }
    show(fee(4) + fee(7));
  19. 19.🧰 What does this code show?
    function greet(name) {
      return "Well done, " + name + "!";
    }
    show(greet("Arjun"));     (a) Well done, name! (b) greet (c) Well done, Arjun! (d) Arjun
  20. 20.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(70, 4));
  21. 21.🧰 What number does this code show?
    function triple(n) {
      return n * 3;
    }
    show(triple(21));
  22. 22.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(20, 3));
  23. 23.🧰 What does this code show?
    function greet(name) {
      return "Welcome, " + name + "!";
    }
    show(greet("Arjun"));     (a) Welcome, name! (b) greet (c) Welcome, Arjun! (d) Arjun
  24. 24.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(14));
  25. 25.🧰 In function tip(bill), what is bill? (a) a loop (b) a screen (c) an event (d) a parameter
  26. 26.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 60;
    }
    show(fee(9) + fee(10));
  27. 27.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 20;
    }
    show(fee(12) + fee(6));
  28. 28.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 30;
    }
    show(fee(12) + fee(4));
  29. 29.🧰 What number does this code show?
    function double(n) {
      return n * 2;
    }
    show(double(40));
  30. 30.🧰 How do you run (call) a function called greet? (a) greet() (b) greet[] (c) run greet (d) #greet
  31. 31.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 30;
    }
    show(fee(6) + fee(5));
  32. 32.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(4) + points(5));
  33. 33.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(75, 4));
  34. 34.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 20;
    }
    show(fee(9) + fee(7));
  35. 35.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Riya"));     (a) Riya (b) greet (c) Hello, name! (d) Hello, Riya!
  36. 36.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Arjun"));     (a) Hello, name! (b) Arjun (c) greet (d) Hello, Arjun!
  37. 37.🧰 A museum app works out the entry fee. What number does this code show?
    function fee(age) {
      if (age < 5) {
        return 0;
      }
      return 30;
    }
    show(fee(12) + fee(12));
  38. 38.🧰 What does this code show?
    function greet(name) {
      return "Hello, " + name + "!";
    }
    show(greet("Kabir"));     (a) Hello, name! (b) Hello, Kabir! (c) Kabir (d) greet
  39. 39.🧰 What number does this code show?
    function total(price, qty) {
      return price * qty;
    }
    show(total(35, 3));
  40. 40.🧰 What number does this code show?
    function points(stars) {
      return stars * 10 + 5;
    }
    show(points(2) + points(1));

Answer key

  1. 70
  2. 60
  3. a named block of code
  4. 108
  5. 30
  6. Hello, Zoya!
  7. to reuse code
  8. 125
  9. 10
  10. 80
  11. Well done, Zoya!
  12. Hi, Arjun!
  13. 50
  14. sends back a value
  15. 0
  16. 44
  17. 0
  18. 40
  19. Well done, Arjun!
  20. 280
  21. 63
  22. 60
  23. Welcome, Arjun!
  24. 28
  25. a parameter
  26. 120
  27. 40
  28. 30
  29. 80
  30. greet()
  31. 60
  32. 100
  33. 300
  34. 40
  35. Hello, Riya!
  36. Hello, Arjun!
  37. 60
  38. Hello, Kabir!
  39. 105
  40. 40

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